SPINS

SPINS

Spins are just plane fun In the ACRO II. Every day I go flying, I do at least one spin. I think everyone should learn spins and, of course, recoveries from them. I dont compete and I am not sure if my entry to a spin is competition caliber, but it works well and it is the spin itself that is the fun part. Who cares about entries anyway?

I like to do five turn spins, or more, so I generally climb to 2500 ft. AGL and acquire straight and level flight prior to entry. Full recovery will then be 500 to 1000 ft. AGL for the five turn spin. IF THIS IS YOUR FIRST SPIN ATTEMPT, GET PLENTY OF ALTITUDE; FIVE OR SIX THOUSAND FEET.

I understand that competition entries are supposed to have no pitch-up prior to the wing drop at the beginning of the maneuver. This is where mine may differ. I reduce the power to idle, maintain altitude during the deceleration by feeding in up-elevator until stall speed is reached the nose will come up if altitude is maintained to provide a goad true stall before spin entry. Ailerons remain neutral throughout the maneuver.As the stall is reached, use rudder to keep the nose on heading a second or two after full aft stick is in. Then quickly feed in rudder, (dont kick it in), the wing should drop on its own, and the spin is started. Hold the full aft stick arid full rudder, and count the turns or half turns aloud. The spin will develop and be fully stable in about two turns. What is happening as the spin develops is the forward speed at the time of spin entry is gradually dissipated to zero, and a true vertical descent is finally established after about two turns. The changing picture out of the windshield for that first two turns is just due to the changing forward ground speed component.

Upon reaching the last half of the last turn of the spin, recovery is initiated by applying opposite rudder, and the rotation should slow a small but perceptible amount. With one quarter turn remaining, break the stall by neutralizing elevator, and the machine should stop rotating right on heading. Fly the airplane on a perfect vertical down line for several hundred feet as speed builds, and then begin the pull-up to level flight adding power slowly as the pull begins.

Always begin recovery with rudder, and then follow with elevator. If the opposite sequence is used, the rate of will increase immediately when elevator is relaxed, and then the rotation w~ net stop promptly when opposite rudder is applied, but may continue for another one or two turns. Because of the unpredictable nature of the elevator first recovery, it is seldom used in competition, air shows, or practice. In order to get the rotation to stop exactly on the desired heading, it will be necessary to determine the precise point to begin recovery. It will vary somewhat according to airplane rigging, technique, etc. You will just have to practice until you get it nailed. But hey, thats what weekends are for.I generally always spin to the left because any propeller gyroscopic forces, (small at idle power settings), are in a direction to pitch the nose up slightly and help keep the wing stalled. In fact adding power, generally full power, will bring the nose up to almost horizontal for a flat spin to the left. Ailerons are also in the flat spin to level the wings, i.e. right aileron for spins to the left. For a normal direction engine, (clockwise rotation), flat spins can only be done to the left for upright spins, and to the right for inverted ones. But for now lets keep the power at idle, and do normal spins.

I do not perform flat spins in my ACRO ii because of the extreme stress placed on the crankshaft by the gyroscopic forces encountered at high RPMs. It is about the same as trying to lift the airplane by the propeller alone a lot of force. Mine has a hollow crank, and it isnt worth the risk! So be sure the engine is at idle throughout the spin.

Inverted spins are similar to upright spins except they are more thrilling and the G meter will read negative during the spin. I enter them inverted, but otherwise the same as an upright spin. It necessary, loosen your shoulder harness enough so that you can push the stick full forward as the airplane reaches stall speed. This is important, because less than full down elevator will make the spin rotation much faster, recovery less predictable, and the whole affair definitely more exciting, maybe too exciting.Anyway, keep the FULL down elevator in and feed in full (right) rudder when the stall is reached. Hold everything, (ailerons neutral), and wait for it to develop. This is truly an exciting and fun maneuver, but if attempted by yourself for the first time, do as I did, and practice it in your mind many, many times to prepare yourself mentally for the experience. The axis of rotation will be above your head, but try not to focus your attention there. Remember that in an upright spin you cant see the spot on the ground where the center of rotation is located, and it is not necessary to see it ~ the Inverted spin either. Instead, keep yaw eyes and attention focused on lie earth directly over the nose of the airplane. You will note that the ground is moving in the same direction as the rudder you are holding in. It you look out the top of the canopy, the earth will appear to rotate in the opposite direction, and may confuse you, so keep those eyes just over the nose. Right over the nose of the airplane will always give you the direction of the spin, upright or inverted.

Recovery is similar to upright spins; first opposite rudder, then neutralize elevator. Hold a true vertical down line, and then recover to level flight. I want to caution you here with respect to G loading on your body. The inverted spin will probably be somewhere around two Gz negative, and if sustained for five or six turns, will be 15 to 20 seconds duration. A positive G pull-up during recovery may well reach three Gz. the total excursion will then be five Gz, (from -2 to +3), and this does not seem like much especially when compared to a five G loop which we do routinely. However, I must point out that it is the total G change in the positive direction which tends to cause gray-out and that sleepy feeling. A five G loop, however, only has a change of four Gz because it starts at plus one and peaks at plus five. Thus, a negative two G spin followed by a positive three G pull-up is similar to a six G loop, not a five G one. Believe me, the old bod can tell the difference in that one extra G! It really is not that big of a deal, but you should be aware of it.

I highly recommend the Gene Beggs emergency spin recovery technique it you get lost and cant seem to recover the spin. This technique works on the ACRO II, and is used as follows: (1) Make sure power is reduced to idle; (2) Let go of the stick; (3) Look directly over the nose and put in rudder opposite to the direction of rotation; (4) When rotation stops, recover from the dive. It works for any spin, however, if there is a passenger in the front seat, you cannot be certain that he is not touching the stick, therefore, you cannot assume that letting go of the stick will work. You must be prepared to do the correct thing with the elevator/ailerons and overpower him if necessary.

Crossover spins are also great fun. You may not want to do them, but you should at least think about them, because a botched spin recovery could easily turn into a crossover spin.unknowingly! This is a spin which is changed from upright to an inverted spin; the picture over the nose will reverse directions; and the G meter will also reverse. You can crossover between modes as often as you have altitude and desire for.Use a small model airplane in your hands to see how the crossover spin works. You will note that a ground observer will not see a change in direction of rotation of the spin, but merely a flop over in attitude. The pilot does however see the direction of rotation changes when looking over the nose.Because of the relative ease with which the airplane crosses over in the other mode, it is easy to see why spin recoveries are sometimes botched. An over-excited state of mind, confusion, over-exuberance on the controls, and other factors could easily create an unintentional spin crossover. If you arent paying close attention, you could miss it and find yourself recovering from the wrong spin, which means you are now holding in PRO-spin inputs and not recovery inputs. That has happened many times, and is what finally led to the Beggs recovery technique. More than once an airplane has recovered itself as the pilot let go of the stick to prepare to bail out from and unrecoverable spin!!!Well thats about all I have for now. Keep flying, keep practicing, and keep grinin!!